This invention relates to a sealed type motor compressor for use with refrigerators, air conditioners and the like, and more specifically to such motor compressors in which a refrigerant gas is delivered directly to a cylinder through a suction muffler from a suction pipe.
In prior art motor compressor, a sealed enclosure is used as a low pressure vessel such that a suction refrigerant gas of low temperatures and low pressure returned through a suction pipe is temporarily stored in a space defined by a sealed enclosure and is then sucked into the suction side of a compressor section. However, such temporary storage of the suction refrigerant gas in the sealed enclosure causes the gas to be exposed to heat generated from the motor section and the compressor section, so that when sucked into the compressor section, the gas becomes substantially high in temperature. Thus the discharge refrigerant gas becomes correspondingly high in temperature to have a disadvantageous influence on itself as well as on a lubricant oil and other elements and to lower the volumetric efficiency of the compressor section.
In an effort to eliminate the above drawback, direct supplying of a suction refrigerant gas into a compressor section is well-known as in U.S. Pat. Nos. 4,086,032 to Nishioka et al, and 4,242,056 to Dyhr et al. However, such arrangement for directly delivering the suction refrigerant gas to a suction muffler or a cylinder is unfavorable in that connections therefor become complicated and assembly thereof is troublesome. In addition, in case the suction refrigerant gas is directly delivered to the cylinder, liquid refrigerant and circulating oil contained in the refrigerant gas flow directly into the compressor to cause liquid compression and oil compression which can possibly be sources for great troubles such as failures of valve portions, a crank shaft and a connecting rod. In dealing with the problem, Dyhr et al patent proposes the provision of an oil-gas separator outside the compressor casing, which makes the apparatus large in size.